Spinning Position With Fibre Guidance Element

ABSTRACT

The invention relates to a spinning position ( 6 ), on a jet spinner, comprising a fibre guidance element ( 3 ). According to the invention, the splaying of the outer fibres of the fibre composite ( 1 ) for introduction, may be increased, and hence the quality of the yarn increased and also jamming of the fibre elements lying parallel to the guide element ( 34 ) may be avoided, whereby the introduction direction ( 34 ) of the fibre composite ( 1 ) is inclined to the direction of the fibre guide surface ( 5 ) at an entry edge ( 32 ) by an angle alpha and the entry edge ( 32 ) is arranged within the fibre guide element ( 3 ).

The invention relates to a spinning position with a fiber guidanceelement according to the preamble of patent claim 1.

The present invention relates to the field of air-jet spinners. Air-jetspinners have a multiplicity of spinning positions. At every spinningposition, a yarn is spun from an introduced fiber sliver. In this case,the fiber sliver is first attenuated, that is to say the amount of fiberper unit of length is reduced by drafting. Then the attenuated fiberstructure is spun into a yarn at the spinning position by impartingtwist. For this purpose, the spinning position has a fiber guidanceelement with a fiber guiding surface, which guides the fiber structureinto a swirl chamber, where a yarn is produced in a spindle by the knownvortex air-spinning process.

Owing to the very high speeds of the fiber structure at the transitionfrom the drafting system into the spindle, the aim is to design theentry into the fiber guidance element upstream of the spindle optimally.High drafting system speeds lead to strong air flows in the region ofthe nip line of the delivery rollers. These air flows may lead tobreaking away of the fiber structure. In FIG. 1 there is shown a fiberguidance element designed as a sleeve 3 with a fiber guiding surface 5arranged inside. From the pair of delivery rollers 2 of the upstreamdrafting system, a fiber structure 1 is guided through the sleeve 3.

EP 1 335 050 A2 proposes for this a sleeve in which two mutuallyinclined fiber guiding surfaces are arranged and, as a result, form adeflecting location inside. The deflecting location, formed as an edge,has the effect of increasing the proportion of free fiber ends on thesurface of the fiber structure, by these ends lifting off. These freefiber ends are taken up by the vortex flow before the spindle.Increasing the proportion of free fibers also has the effect ofincreasing the proportion of wrapping fibers of the yarn and, as aresult, the quality of a yarn spun in this way can be improved. Althoughthis deflecting location improves the quality of the yarn, it doesnothing to contribute to improving the flow conditions where the fiberstructure 1 enters the sleeve 3. When the fiber structure 1 enters thefiber guidance element 3, there is in particular also the risk that thefibers lying parallel to the direction of introduction 34 will becomejammed at edges that are necessarily present.

The present invention is based on the object of providing a spinningposition with a fiber guidance element and of providing a fiber guidanceelement with which the flow conditions even at the transition from thedrafting system to the fiber guidance element are improved, in ordersubsequently to achieve better conditions for the spinning of the fiberstructure.

This object is achieved by the spinning position provided in patentclaim 1 and by the fiber guidance element provided in patent claim 8.

The solution according to the invention, whereby

the direction of introduction of the fiber structure is inclined by anangle of inclination in relation to the direction of the fiber guidingsurface at a deflecting location, for example at an entry edge, and thedeflecting location is arranged inside or at the edge of the fiberguidance element;

produces significantly improved flow conditions and, in particular, arolling or rocking motion of the fiber structure can be effectivelyinhibited as a result. The deflecting location, for example an entryedge, may be arranged at the edge of the fiber guidance element, i.e. atthe end face of the fiber guidance element (the end face 33 from FIG. 2described below), and by being set back or suitably positioned insidethe fiber guidance element.

How the exit of the fiber guidance element may be designed is left openby the invention. This can take place according to the teaching ofdocument 1 335 050 A2. However, this configuration of the exit is notprescribed as obligatory by the invention.

Advantageous embodiments of the invention are provided in furtherclaims.

The invention is explained in more detail below by way of example on thebasis of a drawing, in which

FIG. 1 shows a representation of a fiber guidance element and a pair ofdelivery rollers of a spinning position according to the prior art in EP0 854 214 A2 and EP 1 335 050 A2;

FIG. 2 shows a sectional representation of the fiber guidance elementaccording to the invention at a spinning position;

FIG. 3 shows a sectional representation that is more detailed than FIG.2 of a fiber guidance element according to the invention.

To illustrate the stated problem and the solution provided by thepresent invention, a spinning position 6 of an air-jet spinner with apair of delivery rollers 2 and a fiber guidance element 3 formed as asleeve is shown in FIG. 1 in a perspective view. A fiber structure 1 isguided through the fiber guidance element 3 and is subsequently spuninto a yarn by imparting twist in the spindle 7 (not represented). Thetask of the fiber guidance element 3 is to introduce the fiber structure1 optimally to the subsequent swirl chamber 36, in order that a yarn canbe formed there by means of an air flow.

In the following context, the terms fiber guidance element 3 and sleeve3 are used synonymously.

A fiber guidance element 3 is shown in FIG. 2. The fiber structure 1 istransported in the direction 34 to the fiber guidance element 3. Inorder to achieve still better splaying of the edge fibers, a deflectionis provided at the entry edge 32. The entry edge 32 is formed by aninclination between the direction of introduction 34 and the fiberguiding surface 5, arranged in the sleeve 3, and is arranged inside saidsleeve 3. In this exemplary embodiment, an exit edge 17 is alsoprovided, in order to achieve additional splaying of the edge fibers.Provided at the end of the exit edge 17 is a twist stop 38. However, howthe exit and the following introduction into the inlet mouth 9 of thespindle 7 must be designed is left open by the present invention.Arranged ahead of the inlet mouth 9 in the swirl chamber 36 is an airentry opening 37. Arranging the entry edge 32 inside the fiber guidanceelement 3 makes it particularly advantageous to design the entry with arun-in ramp 39 in such a way that the fiber structure 1 cannot becomejammed as it enters.

Particularly advantageous dimensional specifications for the arrangementof the entry edge 32 are given below; reference is thereby made to FIGS.2 and 3 simultaneously. It should be noted that, both together and ontheir own, these dimensional specifications make advantageous conditionspossible for the entry of the fiber structure 1 into the sleeve 3:

-   i) The angle of inclination α between the fiber guiding surface 5    and the direction of introduction 34 of the fiber structure 1    preferably lies in a range of values of 5°<=α<=85°, with preference    5°<=α<=70°, with particular preference 5°<=α<=25°.-   ii) The direction of introduction of the fiber structure is inclined    with respect to the plane of the drafting system by an angle β,    which preferably lies in a range of values of 0°<β<=10°.-   iii) With reference to the plane 35, which is defined by the axes of    the two delivery rollers 2, the entry edge 32 is at a distance a    from said plane 35 which preferably lies in a range of values of 9    mm<=a<=13 mm.-   iv) The entry edge 32 is arranged with respect to the usually    cylindrical shape of the sleeve 3 at the distance b from the upper    end face 33 of the sleeve 3. The distance b thereby preferably lies    in a range of values of 0.01 mm<=b<=4 mm.-   v) With respect to the plane 30 of the drafting system, the entry    edge 32 is at a distance c which preferably lies in a range of    values of 0<=c<=3 mm.-   vi) The run-in ramp 39 is inclined with respect to the fiber guiding    surface 5 by an angle γ. The range of values preferably lies in a    range of values of 100°<=γ<=150°.

As explained above, the values specified can be used both individuallyfor the spinning position 6 or for the fiber guidance element 3 and incombination. How the fiber guidance element 3 is to be structurallydesigned is left open by the invention, for example a rounding may beperformed at the entry edge 32.

LIST OF THE REFERENCE NUMERALS AND ABBREVIATIONS USED

-   1 fiber structure-   2 pair of delivery rollers-   3 fiber guidance element-   4 fiber guiding channel-   5 fiber guiding surface-   6 spinning position-   7 spindle-   9 inlet mouth-   17 deflecting location, exit edge at the fiber guiding surface of    the fiber guidance element-   30 plane of drafting system-   31 nip line-   32 entry edge at the fiber guiding surface 5 of the fiber guidance    element 3-   33 upper end face of the fiber guidance element 3-   34 direction of introduction of the fiber structure before entry    into the fiber guidance element 3-   35 plane formed by the axes of rotation of the delivery rollers 2-   36 swirl chamber-   37 entry opening air flow-   38 twist stop-   39 run-in ramp-   α angle between fiber guiding surface 5 and direction of    introduction 34 of the fiber structure-   β angle between direction of introduction of the fiber structure and    plane 30 of drafting system-   γ angle between run-in ramp 39 and fiber guiding surface 5-   a distance of entry edge 32 from plane which contains the axes of    rotation of the delivery rollers 2 of the drafting system-   b distance of entry edge 32 from upper end face 33 of the sleeve 3-   c distance of entry edge 32 from plane of drafting system 30

1. A spinning position (6) of an air-jet spinner for producing a yarnfrom a fiber structure (1), the spinning position (6) having a fiberguidance element (3) with a fiber guiding surface (5) contained therein,to which the fiber structure (1) is introduced; characterized in thatthe direction of introduction (34) of the fiber structure (1) isinclined by an angle of inclination α in relation to the direction ofthe fiber guiding surface (5) at a deflecting location (32), preferablyan entry edge (32), and in that the deflecting location (32) is arrangedinside or at the edge (33) of the fiber guidance element (3). 2-11.(canceled)